The present invention relates to a self contained disposable dental tray for taking impressions of teeth and associated soft tissue, the materials therein, methods for its manufacture and the methods for using it to make impressions of teeth and associated soft tissue. At present, impressions of teeth and associated tissue are taken using room temperature vulcanized rubbers (RTVRs) that harden rapidly when mixed with hardener, generating temperatures which are not physiologically harmful to soft tissue. The materials and technology of taking dental impressions are disclosed in KIRK OTHMER' ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY 3rd edition volume 20 pages 922 and 962 and are incorporated herein by reference. Further examples are disclosed in U.S. Pat. Nos. 3,453,242, 4,093,555; 4,167,618; 4,532,268; 4,009,687; 4,532,268 and are incorporated by reference herein.
In order to part the teeth from the impression, it is obviously mandatory that the impression adheres better to the tray than to the teeth. Currently to insure this, a layer of adhesive is placed at the bottom of the tray and then mixed RTVR and its Hardener are charged into the tray. A recent innovation, involves the application of self sticking dots of felt to replace the need for adhesive.
The RTVR's currently used are : polyimines from aziridino terminated polyethers, polysulfides, addition cured vinyl terminated polysiloxanols, and condensation cured polysiloxanols. These are supplied as a two part system, the hardened in one package and the RTVR in a second package. Modifiers and accelerators are also added. At present these two part systems are being sold as a single stroke double cylinder dispenser which simultaneously proportions and mixes the RTVR and hardener. The use of barrier layers between reactive materials to prevent premature mixing, when using a ome package system, is disclosed in U.S. Pat. No. 2,982,396 and is incorporated herein by reference.